alicia campbell. climate and the collapse of maya civilization haug et al, 2003 pre-classic period...

Climate change, public health and

politics 

Alicia Campbell

Climate and the Collapse of Maya Civilization Haug et al, 2003

Pre-Classic period c2000BC to AD 250

Classic period AD 250 to AD950 Foreign invasion Peasant revolt Epidemic disease Overpopulation Climate Change

Drought Terminal Classic

Collapse

The Maya civilization developed in a seasonal desert

and depended on a consistent rainfall cycle to support agricultural production.

Most of the rain falls during the summer, when the ITCZ sits at its northernmost position over the Yucatan.

Maya seasonal water storage strategies: Rainfall catchment Quarries and excavations converted into water reservoirs Topographic highs to use the hydraulic gradient to

distribute the water from canals into complex irrigation systems

Dependence upon seasonal rainfall

Ocean Drilling Program, Cariaco

Basin Visibly laminated sediments

Light-colored laminae consist mostly of biogenic components deposited during the dry winter-spring upwelling season, when the ITCZ is located at its southernmost position

Dark laminae are deposited during the regional rainy season (summer-fall), when the ITCZ migrates to its most northerly position, almost directly over the Cariaco Basin. Dark-colored laminae have record higher inputs of Ti

Bulk Ti content ≈ wet conditions

High sedimentation rate, high resolution (bi-monthly)

Tripartite theory of city abandonment:

Based on the last dates carved into natural monuments

Separate phases of collapse at AD 810, AD 860 and AD 910

Cariaco Record results show: Drought at AD 810, AD 860, AD 910 Short, but severe droughts in an overall dry

period

Classic period-environmental carrying capacity Distinct mutli-year droughts + dry period =

drawn out, regionally variable collapse Effecting cities with artificial water systems,

limited access to groundwater more Undermining Maya institution of governance

A Test of Climate, Sun, and CultureRelationships from an 1810-YearChinese Cave Record Zhang et al, 2008

Asian Monsoon (AM) Affects ≈ 1/3 of the

world’s population Warm/wet summer,

cold/dry winter

Stalagmite from Wanxiang Cave, China Located on the fringes of the area currently

affected by the summer monsoon and is thus sensitive to and integrates broad changes

High growth rate, high uranium concentrations, and low thorium concentrations allow high oxygen isotope resolution (δ18O) and high-precision 230 Th ages (age certainty)

The proxy

Strong:first several decades of the Northern Song Dynasty (increased rice cultivation and dramatic population increase)

Weak:Final decades of the Dynasties

-Tang, -Yuan, -Ming

(popular unrest)

AM weakening since ~1960 Anticorrelating with NH temperature (rising) Dominant forcing of AM variability may have

changed from natural to anthropogenic causes Black carbon-lower troposphere cooling +

mid/upper troposphere heating = reduction in Asian Monsoon precipitation

Differential sulfate aerosol loading (indirectly) can shift tropical rainfall southward (weakening AM)

Modern Climate Change

“The greatest global health threat of the 21st

century” Lancet and University College London

Institute for Global Health Commission Medium-risk scenarios predicting 2–3°C rises

by 2090 and 4–5°C rises in northern Canada, Greenland, and Siberia.

Direct and Indirect health challenges Six main aspects

Managing the health effects of

climate change Costello et al, 2009

Key Topics

Six Aspects of Health Challenges

Changing patterns of disease and mortality

Food Water and sanitation Shelter and human

settlements Extreme events Population and

migration

Key Challenges to form a Policy Response Framework

Informational Poverty and equity-

related Technological Sociopolitical Institutional

Changing patterns of disease and mortality Heat waves

Heat stroke Heat stress Ex: “The heatwaves

of 2003 in Europe caused up to 70 000 deaths, especially from respiratory and cardiovascular causes.”

Increased frequency of infectious vector-borne diseases

tick-borne Encephalitis dengue fever Cholora Lyme, West Nile

Ex: Malaria: rate of pathogen maturation

and replication within mosquitoes

density of insects in a particular area

likelihood of infection

Models and scenarios to estimate that 260–

320 million more people will be affected by malaria by 2080

Mosquito abundance is amplified with warming, with an over ten-fold increase with every unit increase (0·1°C) in temperature.

Malaria

Food

After the rise in food prices in 2008, 100 million to 850 million—might suffer hunger or food insecurity.

According to the UN World Food Programme, the number of food emergencies every year has increased from an average of 15 during the 1980s to more than 30.

Ex: “Corn and soy bean yields in the USA fell by 17% for every degree rise in growing season temperature.”

“Harvests of staple food crops, such as rice and maize, could fall between 20% and 40% as a result of increased temperatures during the growing season in tropical and subtropical regions.”

Half of the world’s population could face severe food shortages by the end of the century

Ex: In Delhi, 15 million people face serious

water shortages, with water being transported up to 300 km. The projected population of this municipality is more than 30 million by 2025.

Water abundance mismatched with population Glacial-fed water catchments (1/6 world

population) Water shortages versus increased flooding

Water & Sanitation

Urban settlements Access to utilities Population centers on coasts Mass displacement, refugees Cities at risk from floods or sea level rise:

Alexandria (Egypt), Cotonou (Benin), Dhaka (Bangladesh), Lagos and Port Harcourt (Nigeria), Abidjan (Côte d’Ivoire), Mombasa (Kenya), Buenos Aires (Argentina), and Bamenda (Cameroon)

Shelter

The number of great weather-related disasters

has climbed from an average of less than two per year in 1950 to more than six in 2007.

Over the same period, average annual economic losses have risen from less than $5 billion to more than $60 billion.

Affecting: health, food, water, shelter, etc…

Extreme Events

World population is likely to increase from the

current 7 billion to 9.2 billion in 2050 Population increases in less developed

countries Ex: “It is estimated that 72% of the dwellers in

African cities live in slums, which, having poor drainage facilities, are especially prone to flooding and ill health”

Population

“According to the UK Government

commissioned Stern review on the economics of climate change in 2006, if we do everything we can now to reduce global greenhouse gas emissions and ensure we adapt to the future effects of climate change, the average estimated cost is 1% of the world gross domestic product (GDP) every year.

However, if we do nothing, the effects of climate change could cost 5–20% of the world GDP every year.”

Costs

Any adaptation should sit alongside the need for

primary mitigation: reduction in greenhouse gas emissions increase carbon biosequestration through reforestation improved agricultural practices.

Inputs from all sectors of government and civil society, collaboration between many academic disciplines, and international cooperation Public health Ex: exploit African ground water (currently only 4%

exploited), produce less beef, urban development, less coastal development, etc…

ETHICS

How can we prevent this? Or at least ameliorate the situation